A Phase II Study Evaluating the Efficacy and Safety of XH-S003 Capsules in Patients With Paroxysmal Nocturnal Hemoglobinuria (PNH)

Inclusion Criteria:

• Male or female with aged ≥18 years old;

• Weight ≥40 kg and BMI≥18 kg/m2 ;

• Diagnosed with PNH: with red blood cell or granulocyte clone levels >10% detected byflow cytopy within 6 months prior to screening or during screening;

• Patients who have not previously received any complement inhibitor therayp;

• LDH > 1.5×ULN detected two times during the screening period (interval of 2 to 8weeks);

• Hb meets one of the following conditions: (1) Hb <100 g/L at the first screeningvisit, and subjects receive RBC transfusion because of PNH-related anemia during thescreening period; (2) The average Hb of two tests during the screening period <100g/L (interval of 2~8 weeks);

• Vaccination against Neisseria meningitidis and Streptococcus pneumoniae before thefirst administration. If the subject has not been vaccinated previously or requiresbooster vaccination (according to local vaccination policies), vaccination must beadministered at least 2 weeks before the first administration. If the firstadministration must begin less than 2 weeks after vaccination, preventive antibiotictreatment must begin at least 2 weeks after vaccination;

Exclusion Criteria:

• Subjects with laboratory evidence of bone marrow failure during the screening period (reticulocyte count <100×109/L, platelet count <30×109/L, or neutrophil count <0.5×109/L);

• Subjects receiving other therapies prior to screening who have not achieved thefollowing treatment durations:

• Erythropoietin or immunosuppressants for at least 8 weeks; • Systemiccorticosteroids for at least 4 weeks; • Iron supplements, vitamin B12, or folic acidfor at least 4 weeks; • Anticoagulants: Vitamin K antagonists for at least 4 weekswith stable international normalized ratio (INR) (as determined by theinvestigator), low molecular weight heparin for at least 4 weeks; • Hypoxic-inducingfactor prolyl hydroxylase inhibitors (HIF-PHI) for at least 8 weeks; • Androgens forat least 4 weeks;

• A history of bone marrow/hematopoietic stem cell or solid organ transplantation;

• Alanine aminotransferase (ALT), γ-glutamyl transpeptidase (GGT), or alkalinephosphatase (ALP) >3×ULN at screening; - Positive HIV antibody, active syphilisinfection, positive HBsAg, active HCV infection, or active tuberculosis infection atscreening;

• Known or suspected immunodeficiency diseases or hereditary complement deficiency atscreening;

• A history of Neisseria meningitidis infection;

• Subjects with chronic active or recurrent infections within 1 year prior toscreening;

• Subjects with systemic active bacterial, viral (including COVID-19), or fungalinfections within 2 weeks prior to the first administration; subjects with bodytemperature >38°C within 7 days prior to the first administration;